Wireless Ear Buds With Proximity Sensors

ABSTRACT

Ear buds are provided that communicate wirelessly with an electronic device. To determine the current status of the ear buds and thereby take suitable action in controlling the operation of the electronic device and ear buds, the ear buds may be provided with sensor circuitry. The sensor circuitry may include proximity sensors. The ear buds may each have a housing with a main body portion that is configured to be inserted into the ear of the user and an elongated stem portion that extends from the main body portion. The proximity sensors may include sensors on the main body and sensors on the stem. The proximity sensors may be light-based sensors that emit light that passes through the housing.

This application claims the benefit of provisional patent applicationNo. 62/233,848, filed Sep. 28, 2015, which is hereby incorporated byreference herein in its entirety.

BACKGROUND

This relates generally to electronic devices, and, more particular, towearable electronic devices such as ear buds.

Cellular telephones, computers, and other electronic equipment maygenerate audio signals during media playback operations and telephonecalls. Users often use microphones and speakers in these devices tohandle telephone calls and media playback. Sometimes ear buds have cordsthat allow the ear buds to be plugged into an electronic device.

Wireless ear buds provide users with more flexibility than wired earbuds, but can be challenging to use. It is not always clear whether awireless ear bud is located in a pocket, is resting on a table, or is ina user's ear. As a result, audio signals can sometimes be misdirected.

It would therefore be desirable to be able to provide improved wearableelectronic devices such as improved wireless ear buds.

SUMMARY

Ear buds are provided that communicate wirelessly with an electronicdevice. The electronic device may be a cellular telephone, wristwatchdevice, or other electronic equipment. A wireless link may beestablished between the electronic device and the ear buds. The wirelesslink may be used to transfer audio information between the ear buds andthe electronic device. For example, if the electronic device is beingused for a cellular telephone call or media playback operations, audioassociated with the cellular telephone call or media playback operationsmay be transferred between the electronic device and the ear buds overthe wireless link.

The state of the ear buds may be monitored and corresponding actionstaken in controlling the ear buds and electronic device. For example, ifa user places an ear bud in the ear of the user in response to receivinga cellular telephone call with the electronic device, the telephone callcan be automatically transferred to the ear bud. If the user removes theear bud from the ear during a telephone call or media playbackoperation, the audio for the call or media playback operation can berouted to a speaker in the electronic device.

During use by a user, the ear buds may be stored in a case or pocket,may be rest on a table top, may be inserted into the ear of a user, ormay rest in the ear of a user. To determine the current status of theear buds and thereby take suitable action in controlling the operationof the electronic device and ear buds, the ear buds may be provided withsensor circuitry. The sensor circuitry may include proximity sensors.The ear buds may each have a main body portion that is configured to beinserted into the ear of the user and an elongated stem portion thatextends from the main body portion. The proximity sensors may includesensors on the main body and sensors on the stem.

The proximity sensors may be light-based sensors each of which has alight source such as an infrared light-emitting diode and acorresponding light detector. Infrared light from the light-emittingdiodes can pass through the housings of the ear buds. There may be twoproximity sensors on the main body of each ear bud and two proximitysensors on the stem of each ear bud or other numbers of proximitysensors may be used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of an illustrative system includingelectronic equipment that communicates wirelessly with wearableelectronic devices such as wireless ear buds in accordance with anembodiment.

FIG. 2 is a perspective view of an illustrative ear bud in accordancewith an embodiment.

FIG. 3 is a side view of an illustrative ear bud located in an ear of auser in accordance with an embodiment.

FIGS. 4, 5, and 6 are cross-sectional side views of portions of housingwall structures for ear buds and associated light-based proximitysensors in accordance with an embodiment.

FIG. 7 is a flow chart of illustrative steps involved in calibrating andoperating wearable electronic devices such as wireless ear buds inaccordance with an embodiment.

FIG. 8 is a state diagram showing illustrative operations involved indetermining the current state of wireless ear buds in accordance with anembodiment.

DETAILED DESCRIPTION

An electronic device such as a host device may have wireless circuitry.Wireless wearable electronic devices such as wireless ear buds maycommunicate with the host device and with each other. In general, anysuitable types of host electronic device and wearable wirelesselectronic devices may be used in this type of arrangement. The use of awireless host such as a cellular telephone, computer, or wristwatch maysometimes be described herein as an example. Moreover, any suitablewearable wireless electronic devices may communicate wirelessly with thewireless host. The use of wireless ear buds to communicate with thewireless host is merely illustrative.

A schematic diagram of an illustrative system in which a wirelesselectronic device host communicates wirelessly with accessory devicessuch as ear buds is shown in FIG. 1. Host electronic device 10 may be acellular telephone, may be a computer, may be a wristwatch device orother wearable equipment, may be part of an embedded system (e.g., asystem in a plane or vehicle), may be part of a home network, or may beany other suitable electronic equipment. Illustrative configurations inwhich electronic device 10 is a watch, computer, or cellular telephone,may sometimes be described herein as an example.

As shown in FIG. 1, electronic device 10 may have control circuitry 16.Control circuitry 16 may include storage and processing circuitry forsupporting the operation of device 10. The storage and processingcircuitry may include storage such as hard disk drive storage,nonvolatile memory (e.g., flash memory or otherelectrically-programmable-read-only memory configured to form a solidstate drive), volatile memory (e.g., static or dynamicrandom-access-memory), etc. Processing circuitry in control circuitry 16may be used to control the operation of device 10. The processingcircuitry may be based on one or more microprocessors, microcontrollers,digital signal processors, baseband processors, power management units,audio chips, application specific integrated circuits, etc.

Device 10 may have input-output circuitry 18. Input-output circuitry 18may include wireless communications circuitry 20 (e.g., radio-frequencytransceivers) for supporting communications with wireless wearabledevices such as ear buds 24 or other wireless wearable electronicdevices via wireless links 26. Ear buds 24 may have wirelesscommunications circuitry 30 for supporting communications with circuitry20 of device 10. Ear buds 24 may also communicate with each other usingwireless circuitry 30. In general, the wireless devices that communicatewith device 10 may be any suitable portable and/or wearable equipment.Configurations in which wireless wearable devices 24 are ear buds aresometimes described herein as an example.

Input-output circuitry in device 10 such as input-output devices 22 maybe used to allow data to be supplied to device 10 and to allow data tobe provided from device 10 to external devices. Input-output devices 22may include buttons, joysticks, scrolling wheels, touch pads, key pads,keyboards, microphones, speakers, displays (e.g., touch screendisplays), tone generators, vibrators (e.g., piezoelectric vibratingcomponents, etc.), cameras, sensors, light-emitting diodes and otherstatus indicators, data ports, etc. A user can control the operation ofdevice 10 by supplying commands through input-output devices 22 and mayreceive status information and other output from device 10 using theoutput resources of input-output devices 22. If desired, some or all ofthese input-output devices may be incorporated into ear buds 24.

Each ear bud 24 may have control circuitry 28 (e.g., control circuitrysuch as control circuitry 16 of device 10), wireless communicationscircuitry 30 (e.g., one or more radio-frequency transceivers forsupporting wireless communications over links 26), may have one or moresensors 32, and may have additional components such as speakers 34,microphones 36, and accelerometers 38. Speakers 34 may play audio intothe ears of a user. Microphones 36 may gather audio data such as thevoice of a user who is making a telephone call. Accelerometer 38 maydetect when ear buds 24 are in motion or are at rest.

Control circuitry 28 on ear buds 24 and control circuitry 16 of device10 may be used to run software on ear buds 24 and device 10,respectively. During operation, the software running on controlcircuitry 28 and/or 16 may be used in gathering sensor data, user input,and other input and may be used in taking suitable actions in responseto detected conditions. As an example, control circuitry 28 and 16 maybe used in handling audio signals in connection with incoming cellulartelephone calls when it is determined that a user has placed one of earbuds 24 in the ear of the user. Control circuitry 28 and/or 16 may alsobe used in coordinating operation between a pair of ear buds 24 that arepaired with a common host device (e.g., device 10), handshakingoperations, etc.

In some situations, it may be desirable to accommodate stereo playbackfrom ear buds 24. This can be handled by designating one of ear buds 24as a primary ear bud and one of ear buds 24 as a secondary ear bud. Theprimary ear bud may serve as a slave device while device 10 serves as amaster device. A wireless link between device 10 and the primary ear budmay be used to provide the primary ear bud with stereo content. Theprimary ear bud may transmit one of the two channels of the stereocontent to the secondary ear bud for communicating to the user (or thischannel may be transmitted to the secondary ear bud from device 10).Microphone signals (e.g., voice information from the user during atelephone call) may be captured by using microphone 36 in the primaryear bud and conveyed wirelessly to device 10.

Sensors 32 may include strain gauge sensors, proximity sensors, ambientlight sensors, touch sensors, force sensors, temperature sensors,pressure sensors, magnetic sensors, accelerometers (see, e.g.,accelerometers 38), gyroscopes and other sensors for measuringorientation (e.g., position sensors, orientation sensors),microelectromechanical systems sensors, and other sensors. Proximitysensors in sensors 32 may emit and/or detect light and/or may becapacitive proximity sensors that generate proximity output data basedon measurements by capacitance sensors (as examples). Proximity sensorsmay be used to detect the presence of a portion of a user's ear to earbud 24 and/or may be triggered by the finger of a user (e.g., when it isdesired to use a proximity sensor as a capacitive button or when auser's fingers are gripping part of ear bud 24 as ear bud 24 is beinginserted into the user's ear).

FIG. 2 is a perspective view of an illustrative ear bud. As shown inFIG. 2, ear bud 24 may include a housing such as housing 40. Housing 40may have walls formed from plastic, metal, ceramic, glass, sapphire orother crystalline materials, fiber-based composites such as fiberglassand carbon-fiber composite material, natural materials such as wood andcotton, other suitable materials, and/or combinations of thesematerials. Housing 40 may have a main portion such as main body 40-1that houses audio port 42 and a stem portion such as stem 40-2 or otherelongated portion that extends away from main body portion 40-1. Duringoperation, a user may grasp stem 40-2 and, while holding stem 40-2, mayinsert main portion 40-1 and audio port 42 into the ear.

Audio ports such as audio port 42 may be used for gathering sound for amicrophone and/or for providing sound to a user (e.g., audio associatedwith a telephone call, media playback, an audible alert, etc.). Forexample, audio port 42 of FIG. 2 may be a speaker port that allows soundfrom speaker 34 (FIG. 1) to be presented to a user. Sound may also passthrough additional audio ports (e.g., one or more perforations may beformed in housing 40 to accommodate microphone 36).

Sensor data (e.g., proximity sensor data, accelerometer data or othermotion sensor data), wireless communications circuitry statusinformation, and/or other information may be used in determining thecurrent operating state of each ear bud 24. Proximity sensor data may begathered using proximity sensors located at any suitable locations inhousing 40. FIG. 3 is a side view of ear bud 24 in an illustrativeconfiguration in which ear bud 24 has four proximity sensors S1, S2, S3,and S4. Sensors S1 and S2 may be mounted in main body portion 40-1 ofhousing 40 and sensors S3 and S4 may be mounted on stem 40-2 or othermounting arrangements may be used. In the example of FIG. 3, there arefour proximity sensors on housing 40. More proximity sensors or fewerproximity sensors may be used in ear bud 24, if desired.

Sensors S1, S2, S3, and S4 may use reflected light, capacitancemeasurements, or other measurements to determine whether an externalobject is nearby. During operation, a raw sensor signal (e.g., areflected light signal, capacitance signal, etc.) may be compared to apredetermined threshold. If the raw signal is greater than thethreshold, the sensor output will be positive (i.e., an external objectis in the vicinity of the sensor). If the raw signal is less than thethreshold of the sensor, the sensor output will be negative (i.e., noexternal object is in the vicinity of the sensor).

As shown in FIG. 3, ear bud 24 may be inserted into the ear (ear 50) ofa user, so that speaker port 42 is aligned with ear canal 48. Ear 50 mayhave features such as concha 46, tragus 45, and antitragus 44. Proximitysensors such as proximity sensors S1 and S2 may output positive signalswhen ear bud 24 is inserted into ear 50. Sensor S1 may be a tragussensor and sensor S2 may be a concha sensor or sensors such as sensorsS1 and/or S2 may be mounted adjacent to other portions of ear 50.Sensors S3 and S4 may be located away from ear 50, so that sensors S3and S4 output negative signals when ear bud 24 is inserted into ear 50.

The status of sensors S1, S2, S3, and S4 may be analyzed to helpdiscriminate between possible usage scenarios for ear buds 24 (e.g., anear bud is in a protective case, an ear bud is in a user's pocket, anear bud is being held by the fingers of a user as the user is insertingthe ear bud into ear 50, ear bud 24 is in ear 50, etc.). Based on thisstatus information, appropriate action can be taken by ear buds 24 andelectronic device 10.

With one illustrative arrangement, proximity sensors in ear buds 24 maybe formed using light-based proximity sensors. An illustrativelight-based proximity sensor that has been mounted within housing 40 ofear bud 24 is shown in FIG. 4. As shown in the cross-sectional side viewof FIG. 4, light-based proximity sensor 60 may have a substrate such assubstrate 62. Substrate 62 may be formed from a rigid printed circuitboard (e.g., substrate 62 may be formed from fiberglass-filled epoxy orother rigid printed circuit board material) or may be a flexible printedcircuit (e.g., substrate 62 may be formed from a flexible layer ofpolyimide or a sheet of other flexible polymer). Components may bemounted on substrate 62 for handling proximity sensor signals. Thesecomponents may include light source 64 and light detectors 66.

Light source 64 may be a light-emitting diode such as an infraredlight-emitting diode that emits light 70 that is out of the visiblespectrum (e.g., to avoid distracting the user). Light detector 66 may bea photodetector based on a phototransistor or photodiode and may besensitive to the wavelength of light 70. In the absence of ear 50 orother external object such as external object 74 (e.g., a user's finger,the interior of a pocket, a table top, etc.), light 70 will travel intofree space and will not be reflected towards detector 66. As a result,the output of sensor 60 will be negative. In the presence of ear 50 orother external object 74, however, reflected light 72 from externalobject 74 will be detected by detector 66. The output of sensor 60 inthis situation will therefore be positive. Light 70 (and reflected light72) may be visible light, infrared light, broad spectrum light, narrowspectrum light (e.g., light having a spectral width of less than 20 nmor less than 5 nm), may be ultraviolet light, or may be other suitablelight.

Sensor 60 may be mounted behind a portion of housing wall 40. In theillustrative configuration of FIG. 4, portions 40D of housing wall 40are different than portions 40W of housing wall 40. Portions 40D mayabsorb light 70 and may therefore reduce the signal-to-noise ratio ofreflected signal 72. To enhance the signal-to-noise ratio of proximitysensor 60, infrared-transparent materials may be used in forming windowsin housing 40. For example, portions 40W may be infrared-transparentmaterials (e.g., plastic, glass, etc.), may be portions of housing 40that include microperforations to enhance infrared light transmission(e.g., laser-drilled openings with diameters of less than 75 microns,more than 50 microns, less than 150 microns, or other suitable sizes),or may be other material or structures for enhancing the transmission oflight 70 and the transmission of reflected light 72.

Some of light 70 may scatter when emitted by light source 64, so anoptional light blocking structure such as structure 68 may beincorporated into sensor 60, if desired. Structure 68 may be formed fromopaque plastic, metal, or other opaque materials. Structure 68 may beformed as an integral portion of housing 40, may be a molded plasticmember on substrate 62, may be a member that is attached to substrate 62using adhesive or other suitable mounting arrangements, or may be anyother light blocking structure. Clear polymer or other material may beinterposed between light source 64 and housing 40 and may be interposedbetween housing 40 and light detector 66. The illustrative configurationof FIG. 5, which does not include any polymer or other material betweenthe circuitry of sensor 60 and the inner surface of housing 40, is shownas an example.

FIG. 6 is a cross-sectional side view of housing 40 and sensor 60 in anillustrative configuration in which a portion of housing 40 has beenlocally thinned to enhance light transmission for sensor 60. Housing 40has a thickness of D2 in regions of ear bud 24 that are not aligned withsensor 60. In portions of housing 40 that are aligned with sensor 60,housing 40 is locally thinned and has a thickness D1 that is less thanD2. The value of D2 may be 450 microns, more than 300 microns, more than700 microns, less than 2 mm, or other suitable thickness. The value ofD1 may be 150 microns, more than 100 microns, less than 400 microns, orother suitable thickness). Illustrative polymer 76 (e.g.,infrared-transparent polymer) or other structures may be placed betweensubstrate 62 and the inner surface of thinned portion 40T of housing 40to help secure sensor 60 to ear bud 24 or other mounting techniques maybe used.

Some of light 70 may be scattered into detector 66 by particles or othersubstances in housing 40. Calibration operations may be performed duringmanufacturing or during use of ear bud 24 by a user to remove thissource of noise from the proximity detector signal produced by sensor60. Illustrative steps involved in the calibration and use of proximitysensor data in ear buds 24 is shown in FIG. 7. During calibrationoperations (step 80), the amount of light 70 that is being scatteredback towards detector 66 by housing 40 rather than being reflected backtowards detector 66 by an external object can be ascertained. Inparticular, the amount of light 70 that is scattered rather than beingtransmitted may be measured at step 82. For example, light source 64 maybe modulated using a square wave or other suitable modulating signal inthe absence of an external object. When light source 64 is turned on,detector 66 can measured the scattered light signal from housing 40.When light source 64 is turned off, detector 66 will measure backgroundsignals. Using this technique, the amount of scattered light in sensor60 (e.g., a fraction of the amount of transmitted light 70) may bedetermined and stored in control circuitry 30 for use as calibrationdata (see, e.g., step 84).

At step 86, after the calibration operations of step 80 have beenperformed, ear bud 24 may be used by a user while data is gathered fromproximity sensors S1, S2, S3, and S4 and other sensors and circuitry inear buds 24. The user may store ear buds 24 in a protective chargingcase (e.g., a case having a connector that mates with a correspondingconnector on stem 40-2 or other portion of ear bud 24 to facilitatebattery recharging operations), may store ear buds 24 in a pocket of anarticle of clothing or a bag, may allow ear buds 24 to rest on a surfacesuch as a table top, may pick up and hold ear buds 24 by body 40-1and/or stem 40-2, may insert ear buds 24 into ears 50, and may removeear buds 24 from ears 50.

In each of these different possible usage scenarios, there is apotential for a different set of sensors to be blocked and a potentialfor a corresponding different set of sensors to be unblocked. Theamounts of time that the sensors are blocked and unblocked will alsogenerally vary in different scenarios.

Sensors may be blocked by ears 50, by a user's fingers, by a portion ofa pocket of a case or article of clothing, by a table surface of otherresting surface, etc. For example, if sensors S1 and S2 are positive andsensors S3 and S4 are negative, ear buds 24 and device 10 can concludethat ear buds 24 have been inserted into ears 50 (i.e., sensors S1 andS2 are now resting adjacent to ear 50 and sensors S3 and S4 areuncovered because the user's fingers have released the stems of ear buds24). If sensors S1, S2, S3, and S4 are all negative (as anotherexample), it can be concluded that ear buds 24 are in an enclosed areasuch as the interior of a pocket.

Accelerometer data from accelerometer 38 and/or other information (e.g.,information from microphone 36) may be used to help accurately identifyusage scenarios. As an example, if accelerometer 38 indicates that earbuds 24 are not moving, it can be concluded that ear buds 24 are restingon a table or other non-moving surface. If accelerometer 38 indicatesthat ear buds 24 are moving, it can be assumed that ear buds 24 are notresting on a table. Clock data (e.g., time information, dateinformation, etc.) may be used in conjunction with sensor data,communications status data (e.g., whether an incoming cellular telephoneis being received by device 10), and other information to determinewhich actions should be taken by ear buds 24 and device 10.

At step 88, ear buds 24 and/or device 10 of FIG. 1 may take suitableaction based on the detected state of ear buds 24. For example, if it isdetermined that a user has just placed one of ear buds 24 into ear 50 inresponse to an incoming cellular telephone call to device 10, audioplayback may be transferred from device 10 to that ear bud. A remotewireless link (e.g., a cellular telephone link with a wireless basestation in a cellular telephone network) may be handled by device 10. Alocal wireless link (link 26 of FIG. 1) may be established betweendevice 10 and ear bud 24 to allow ear bud 24 to transmit and receiveaudio. If it is determined that ear buds 24 are located in the pocket ofa user when an incoming call is received on device 10, the incoming callcan be routed to the speaker and microphone of device 10.

In yet another scenario, a user may be using ear bud 24 in ear 50 tohandle a cellular telephone call. A local wireless link (link 26)between ear bud 24 and device 10 may be used to transmit microphone andspeaker audio signals between device 10 and ear bud 24. Device 10 maymaintain a cellular telephone link with remote network equipment. If auser removes ear bud 24 from ear 50 during the telephone call, themicrophone and speaker of device 10 can be switched into use so that thetelephone call can be sustained even though the user is no longer usingear bud 24.

In some situations, the output of sensor S1 may be positive whilesensors S3 and S4 are negative, indicating that ear bud 24 is in ear 50.During media playback, audio may be streamed from device 10 to ear bud24 and presented to the user with the speaker in ear bud 24. Sensors S3and S4 may be used as touch buttons. A user can momentarily block one orboth of these sensors to advance a track, to pause a track that iscurrently playing, or to otherwise control media playback. As thisexample demonstrates, temporarily unused proximity sensors can serve asinput devices.

To discriminate between different usage states, control circuitry 28and/or control circuitry 16 may analyze sensor data from each of theproximity sensors in ear buds 24 and/or the sensors and other circuitryof ear buds 24 and device 10. An illustrative state diagram showing theoperation of the system of FIG. 1 in different states is shown in FIG.8. Control circuitry 28 and/or control circuitry 16 may determine thecurrent operating state of the FIG. 1 system (e.g., ear buds 24 and/ordevice 10) by analyzing the output of sensors S1, S2, S3, and S4 and, ifdesired, additional sensors and sources of operational state informationin ear buds 24 and device 10.

In state 96, ear bud 24 is not in ear 50. While ear bud 24 is out of theuser's ear, the status of sensors S1, S2, S3, and S4 may be monitored.So long as S1 and S2 are not positive while S3 and S4 are negative, itcan be concluded that ear bud 24 is remaining out of the user's ear(i.e., in state 96). Monitoring of S1, S2, S3, and S4 may thereforecontinue.

In response to detecting a positive output from sensors S1 and S2 and anegative output from sensors S3 and S4, it can be tentatively concludedthat ear bud 24 has been placed in ear 50 in a configuration of the typeshown in FIG. 3 and that the user has released stem 40-2. Operations maytherefore transition to state 92 (a state representing the transition ofear bud 24 into ear 50), as indicated by line 110. During state 92, thestatus of sensors S1, S2, S3, and S4 can be monitored to determinewhether the positive state of sensors S1 and S2 and the negative stateof sensors S3 and S4 will be sustained for a threshold amount of time(time T2). The value of T2 may be 0.5 seconds, more than 0.3 seconds,less than 1 second, or other suitable length of time. If any of theoutputs of sensors S1, S2, S3, and S4 changes during state 92, it can beconcluded that ear bud 24 is not in ear 50 and operations may transitionback to state 96, as indicated by line 112.

If sensors S1 and S2 remain positive and sensors S3 and S4 remainnegative for time T2, it can be concluded that ear bud 24 is in ear 50and operations can transition to state 90, as indicated by line 102.During the monitoring operations of state 90, the status of sensor S1(the tragus sensor) or sensor S2 (the concha sensor) can be monitoredand the status of sensors S3 and S4 can be ignored. After ear bud 24 hasbeen placed in ear 50, a user may move in a way that causes sensors S3and S4 to produce a positive output (e.g., due to the presence of hair,a hat, or other obstructions). The output of sensors S3 and S4 istherefore not necessarily representative of the status of ear bud 24during use of ear bud 24 and can be ignored when monitoring the sensorsto determine the current operating state of ear bud 24. Sensors such assensors S1 and S2 are immediately adjacent to the user's ear and aretherefore more representative of whether or not ear bud 24 is in theuser's ear. With one illustrative configuration, sensor S1 may bemonitored and sensor S2 may be ignored along with sensors S3 and S4(e.g., because sensor S1 is more representative of whether or not earbud 24 is present in ear 50). Other sensor monitoring schemes may beused during state 90, if desired (e.g., schemes in which S2 is monitoredbut not S1, schemes in which S1 and S2 are monitored, schemes in whichS1 and S2 are both monitored but are weighted unequally and/or arefiltered using different time-dependent filters, etc.). The arrangementof state 90 of FIG. 8 is an example.

In a scenario in which sensor S1 is being monitored during state 90while the outputs of sensors S2, S3, and S4 are being ignored, anytransition in the state of the output of sensor S1 from positive tonegative indicates that ear bud 24 is potentially being removed from ear50. Operations may therefore transition to state 98, as indicated byline 104.

During the operations of state 98, ear bud 24 is believed to betransitioning out of ear 50. In response to determining during theoperations of step 98 that the S1 sensor output has returned to positivebefore reaching time T1, operations may transition back to state 90, asindicated by line 106 (i.e., it can be concluded that ear bud 24 isstill in ear 50). The value of T1 may be 0.25 seconds, less than 1second, more than 0.1 second, or other suitable amount. The value of T1may be less than the value of T2 or may be more than the value of T2. Ifthe output of sensor S1 remains negative for a predetermined thresholdamount of time (e.g., more than time T1), it can be concluded that earbud 24 is out of ear 50 and operations can transition to state 96.

Information from the monitoring operations and analysis operations ofFIG. 8 can be used to determine which actions to take during theoperations of step 88 (FIG. 7). If desired, other sensor data (e.g.,accelerometer output), cellular telephone call status information(incoming call present, current call active, etc.), and/or othercommunications status information and operating status information maybe used in determining which actions to take. The user of proximitysensor output information from sensors S1, S2, S3, and S4 is merelyillustrative.

The foregoing is merely illustrative and various modifications can bemade by those skilled in the art without departing from the scope andspirit of the described embodiments. The foregoing embodiments may beimplemented individually or in any combination.

What is claimed is:
 1. A wireless ear bud, comprising: a housing; aspeaker in the housing; a concha sensor in the housing; tragus sensor inthe housing; and an accelerometer in the housing that is configured toproduce output indicative of movement of the housing.
 2. The wirelessear bud defined in claim 1 wherein the concha and tragus sensorscomprise light-based proximity sensors.
 3. The wireless ear bud definedin claim 2 wherein the concha and tragus sensors each have an infraredlight-emitting diode and each have a light detector.
 4. The wireless earbud defined in claim 3 wherein the housing comprises a wall and whereinthe infrared light-emitting diodes in the concha and tragus sensors emitinfrared light that passes through the wall.
 5. The wireless ear buddefined in claim 1, wherein the wireless ear bud has a current operatingstate, the wireless ear bud further comprising: control circuitry thatis configured to determine the current operating state by analyzingoutput from at least the concha and tragus sensors.
 6. The wireless earbud defined in claim 1 wherein the control circuitry is furtherconfigured to determine the current operating state by analyzing outputfrom the accelerometer.
 7. The wireless ear bud defined in claim 6wherein the concha and tragus sensors include respective infraredlight-emitting diodes.
 8. The wireless ear bud defined in claim 7wherein the housing has a first portion that is configured to beinserted into an ear and a second portion that extends from the firstportion, wherein the first portion has infrared-transparent portions,and wherein the infrared light from the infrared light-emitting diodespasses through the infrared-transparent portions.
 9. The wireless earbud defined in claim 8 wherein the infrared-transparent portionscomprise plastic and wherein the concha sensor is configure to detectinfrared light that has reflected off of a concha of the ear.
 10. Thewireless ear bud defined in claim 1 wherein the housing has a firstportion that is configured to be inserted into an ear and a secondportion that extends from the first portion, the wireless ear budfurther comprising an infrared light-based proximity sensor in thesecond portion.
 11. An ear bud, comprising: control circuitry; wirelesscircuitry that the control circuitry uses to communicate wirelessly withan electronic device; a housing having a main body portion that isconfigured to be inserted into an ear of a user and a stem portion thatextends from the main body portion; a speaker in the main body portion;a first proximity sensor on the main body portion that monitors whetherthe first proximity sensor is adjacent to the ear; and a secondproximity sensor on the stem portion.
 12. The ear bud defined in claim11 wherein when the main body portion is in the ear, the first proximitysensor produces a positive output indicating that the first proximitysensor is adjacent to the ear and the second proximity sensor produces anegative output indicating that no external object is adjacent to thesecond proximity sensor.
 13. The ear bud defined in claim 12 wherein thefirst proximity sensor is a light-based proximity sensor.
 14. The earbud defined in claim 13 wherein the second proximity sensor is alight-based proximity sensor.
 15. The ear bud defined in claim 14wherein the first and second proximity sensors each include an infraredlight-emitting diode and wherein the infrared light-emitting diodesproduce infrared light that passes through the housing, the ear budfurther comprising an accelerometer in the housing.
 16. An ear bud,comprising: a housing having a main body portion and a stem portion thatextends from the main body portion; a speaker in the main body portion;and at least two proximity sensors on the housing.
 17. The ear buddefined in claim 16 wherein the proximity sensors comprise: first andsecond proximity sensors on the main body portion; and third and fourthproximity sensors on the stem portion.
 18. The ear bud defined in claim16 wherein the proximity sensors include at least a first proximitysensor on the main body portion and at least a second proximity sensoron the stem portion, the ear bud further comprising: an accelerometer;and control circuitry that is configured to analyze outputs from thefirst and second proximity sensors to determine whether the main bodyportion has been inserted into an ear and that is configured to use theaccelerometer to determine whether the housing is moving.
 19. The earbud defined in claim 18 wherein the control circuitry determines thatthe main body portion has been inserted to the ear when at least thefirst proximity sensor has a positive output indicating that the ear isadjacent to the first proximity sensor while at least the second sensorhas a negative output indicating that no external object is adjacent tothe second sensor.
 20. The ear bud defined in claim 19 wherein the firstand second proximity sensors each have an infrared light-emitting diodethat emits infrared light that passes through the housing and each havea light detector.